Steil. — Apogamy in Nephr odium hirtipes , Hk. 131 
Fig. 6. Dorsal views of three prothallia at different stages of development. Paler portion ot 
the prothallium produced before the embryo appears shown in a. In both b and c light areas and 
young embryos shown. 
Fig. 7. A highly magnified view of a small portion of a ‘ light f region. 
Fig. 8. A highly magnified view of a small portion in the neighbourhood of the light region. 
Fig. 9. A highly magnified portion of the apical region of a prothallium after the embryo has 
begun its development, h, multicellular hair. 
Fig. 10. A portion of a prothallium showing the apical region and tracheides, t , in paler 
portion. 
Fig. 1 1. A highly magnified view of a prothallium, dorsal view. multicellular hair produced 
on young embryo. 
Fig. 12. Ventral view of the same prothallium. 
Figs. 13, 14, 15. Young embryos with leaves developed in advance of the roots. 
Fig. 16. An embryo with a root produced in advance of the leaf. 
Fig. 17. Embryo with leaf developed on the dorsal side of the prothallium. 
Fig. 18. An embryo whose root and leaf have grown to about the same length. 
Figs. 19, 20. Young embryos. Leaves in advance of the roots. 
Fig. 21. An embryo with three leaves. 
Fig. 22. A prothallium obtained from a young embryo when a culture was placed in weak 
illumination. petiole-like portion of a leaf; c, flattened outgrowth with elongated cells ; 
a, apical region of gametophytic portion ; f filament. 
Fig. 23. A prothallium on which three apogamously produced embryos were formed. Two of 
these are shown in the photograph. 
PLATE VI. 
Fig. 24. Equatorial plate of the eight-celled stage of the sporogenous cells. 
Fig. 25. Five of the eight sporogenous cells drawn from a longitudinal section of a sporangium. 
In the dividing nuclei some of the chromosomes have passed to the poles. Spindle fibres present. 
Fig. 26. A dividing nucleus of one of the eight cells. The chromosomes have not passed to 
the poles. 
Fig. 27. Four of the eight sporogenous cells drawn from a longitudinal section. The chromo- 
somes are beginning to lose their identity c, clear region where no spindle fibres are present ; 
a, nuclear membrane encloses in each cell the diploid number of chromosomes. 
Fig. 28. Some of the chromosomes have passed to the poles. Spindle fibres and cell-plate 
present. 
Fig. 29. A later stage. Spindle fibres and cell-plate shown on the concave side of the nucleus. 
Fig. 30. A kidney-shaped nucleus. A wall has been produced on the concave side of the 
nucleus. 
Fig. 31. A dumb-bell-shaped nucleus. Wall shown extending to the concavity of the nucleus. 
Fig. 32. A dumb-bell-shaped nucleus. Cell division has progressed still farther than in the 
preceding stage. Cytoplasm on one side of the nucleus divided into two distinct portions, and 
a partial separation of the latter has resulted. 
Fig 33. A dumb-bell-shaped nucleus. There was produced in this case a nearly complete 
nuclear and cell division. 
Fig. 34. A kidney-shaped nucleus. The cell is beginning to round up. The indentation on the 
left-hand side of the figure is the result of incomplete cell division. 
Fig. 35. A spore mother-cell whose nucleus is preparing for synapsis. 
Fig. 36. The nucleus of the spore mother-cell just emerging from synapsis. 
Figs. 37 and 38. The chromosomes during diakinesis. Fig. 37 represents an early stage. 
PLATE VII. 
Fig. 39. A much flattened spore mother-cell at the same stage as represented in Fig. 15. 
Indentation shown on one side as a result of incomplete cell division. 
Fig. 40. The heterotypic division. Spindle, multipolar. 
Fig. 41. Equatorial plate stage of the heterotypic division. Spindle bipolar. 
Fig. 42. An anaphase of the heterotypic division. Some lagging chromosomes shown. 
